Solid Oral Modified Release Dosage Forms Flashcards
What is the Goal of DDS?
Provide a therapeutic amount of drug to a proper site so the desired drug concentration is achieved promptly, then maintained
An important aspect of DDS which targets drugs to specific organs, tissue, cells, or subcellular compartments
Spatial placement
An aspect of DDS that controls the rate of drug delivery to the target site
Temporal Delivery
Products that are enteric-coated tablets or capsules designed to pass through the stomach unaltered → later release of medication in the intestinal tract
Delayed release products
Products that designed to release their medication in a controlled manner, at a predetermined rate, duration, and location to achieve and maintain optimum therapeutic blood levels of drug
Extended - Release Products
BSC Class most suitable for extended - release delivery
BCS Class 1
BCS class that is most challenging to formulate as modified - release products
Class IV drugs
Why is there a need for extended release drugs?
+ Multiple dosing is inconvenient: missed doses, made-up dose, noncompliance
+ Too frequent intake: MTC reached with toxic side efx
+ Missed doses: subtherapeutic levels
Disadvantages of ER Dosage forms
+ Loss of Dose Flexibility
+ Dose Dumping
a general term used to describe dosage forms having drug-release features based on time, course, and/or location that are designed to accomplish therapeutic or convenience objectives not offered by conventional or immediate- release form
Modified - Release
Modified - release example that allows a reduction in dosing frequency from that necessitated
by a conventional dosage form
Extended Release
Designed to release the drug at a time other than promptly after
administration
Delayed - Release
Enteric Coating materials
Fats
Fatty Acids
Waxes
Shellac
Cellulose Acetate Phthalates
Type of Delayed Release Mechanism that:
- Protect the drug in the dosage form from the harmful effects of the gastric environment
- Minimize the irritating effects of certain drugs (e.g., nonsteroidal anti-inflammatory drugs) on the gastric mucosa
- Deliver the drug to the intestine for local effects.
Gastro-resistant coatings
Coatings that respond to enzymatic breakdown are now being considered as
protective coatings suitable for the colonic delivery of polypeptide drugs
Colonic Drug Delivery
Modified release mechanism that contains two single doses of medications, one for immediate release (first dose) and the second for delayed release (second dose)
Repeat Action
Described drug release directed toward isolating or concentrating a drug in a body region, tissue, or site for absorption or for drug action
Targeted Release
True/False:
A. Drugs absorbed slowly are naturally short acting.
B. Drugs with short t1/2 (< 2h) are poor candidates; may require large quantities
False, Naturally Long Acting
True.
Characteristic of Extended Release Products where the drug has a good margin of safety
WIde therapeutic index
Microcrystalline spheres are more durable than other nonpareil seeds.
True
Coating Lipids in ER Technologies
Beeswax
Carnauba Wax
Glyceryl Monostearate
Cetyl Alcohol
Ethylcellulose
ER Tech. Compressed tablets (8 – 10 minitablets) are placed in a gelatin capsule
Multitablet system
Enclosing materials in a wall forming material leading to coacervation (i.e. gelatin)
Microencapsulated Drug
Examples of Wall Forming Material in Microencapsulated Drugs
Gelatin
Polyvinyl Alchohol
Ethylcellulose
Polyvinyl chloride
The primary mechanism of drug release occurs when the polymer swells on contact with the aqueous medium to form a gel layer on the surface of the system
Embedding drug in slowly eroding or hydrophilic matrix system
Drug is released from the matrix by diffusion wherein the plastic form retains its shape during its passage through the alimentary tract
Embedding drug in inert plastic matrix
release the drug in a controlled manner to their specific site of action - retains on the targeted site
Gastroretention forms i.e. tx of H.pylori
An Active (drug) and push (polymeric osmotic agent) layers, operating with the principle of osmotic pressure
Osmotic pump
What factors are not affecting osmotic pump?
Gastrointestinal acidity
Alkalinity
Fed Conditions
Gastrointestinal motility
Example of Osmotic Pump
Adalat 30
Initial dose (outer shell or coating) of the drug is released
immediately and a second dose (inner core) is released later
Repeat Action Tablets
T/F. It is normal to find empty shells or ghosts from osmotic tablets in the stool.
True
